Try remaking the signs using /iteminfo to get each item's ID. Portal page lists your Brewing Stand separated from mine, for example, which means our shops have different IDs for them (also, my Brewing Stand shop sign is working fine).

I took the id's from the official mine craft Id page, as well as checked with the ones used on the mall price. Last night the stand matched up with the one you used but now it's on its own page again...that's not even mentioning the many ones that also match up but keep saying I have no stock of it. All of which I redid last night, had it say it was working, only to wake up and have it all be broken again